N-acetylcysteine and zinc sulphate abate di-2-ethylhexyl phthalate-mediated reproductive dysfunction in rats:Focus on oxidative and sex hormone receptors mechanisms

Objective:To investigate the potential of N-acetylcysteine(NAC)and zinc sulphate(ZnSO_(4))in mitigating reproductive dysfunction caused by di-2-ethylhexyl phthalate(DEHP)in rats and to understand the underlying mechanisms,specifically oxidative stress and sex hormone receptor activity.Methods:Thirty-five male Wistar rats were randomly divided into five equal groups(n=7 per group).Group 1 was administered 0.5 mL of distilled water and served as the control group.Group 2 was given only DEHP(750 mg/kg/day),while group 3,4 and 5 were given DEHP(750 mg/kg/day)plus NAC(100 mg/kg/day),DEHP(750 mg/kg/day)plus ZnSO_(4)(0.5 mg/kg/day),and DEHP(750 mg/kg/day)plus NAC(100 mg/kg/day)as well as ZnSO_(4)(0.5 mg/kg/day),respectively.All treatments lasted for 21 days.Samples were obtained after the rats were sacrificed,and hormones levels in the serum and markers of oxidative stress in the testicles were analyzed using the enzyme-linked immunosorbent assay.The amount of androgen receptors in the testicles was determined by immunohistochemistry,and the susceptibility of testosterone and DEHP to bind to androgen receptor and 5α-reductase was determined by molecular docking studies.Results:DEHP decreased reproductive hormones,testicular antioxidant enzymes,increased malondialdehyde levels,and negatively impacted histology of the pituitary and testes.NAC or ZnSO_(4) treatment showed a marked improvement in testicular antioxidant status and hormone levels,as well as a positive effect on the histology of the pituitary and testes.The combination of both treatments appeared to be more effective.The affinity of DEHP to bind to androgen receptors may lead to disruption of androgen receptor signaling,which can further result in dysfunction of hormones related to androgen.However,NAC is more likely to form stronger binding interactions with follicle stimulating hormone and luteinizing hormone receptors,as well as gonadotropin-releasing hormone receptors,when compared to DEHP.Conclusions:The possibility that NAC and ZnSO_(4) could downregulate DEHP-induced sex hormone changes is suggested by their potential to reduce toxicity.

Green tea polyphenols alleviate di-(2-ethylhexyl)phthalate-induced liver injury in mice

BACKGROUND Di(2-ethylhexyl)phthalate(DEHP)is a common plasticizer known to cause liver injury.Green tea is reported to exert therapeutic effects on heavy metal exposureinduced organ damage.However,limited studies have examined the therapeutic effects of green tea polyphenols(GTPs)on DEHP-induced liver damage.AIM To evaluate the molecular mechanism underlying the therapeutic effects of GTPs on DEHP-induced liver damage.METHODS C57BL/6J mice were divided into the following five groups:Control,model[DEHP(1500 mg/kg bodyweight)],treatment[DEHP(1500 mg/kg bodyweight)+GTP(70 mg/kg bodyweight),oil,and GTP(70 mg/kg bodyweight)]groups.After 8 wk,the liver function,blood lipid profile,and liver histopathology were examined.Differentially expressed micro RNAs(miRNAs)and mRNAs in the liver tissues were examined using high-throughput sequencing.Additionally,functional enrichment analysis and immune infiltration prediction were performed.The miRNA-mRNA regulatory axis was elucidated using the starBase database.Protein expression was evaluated using immunohistochemistry.RESULTS GTPs alleviated DHEP-induced liver dysfunction,blood lipid dysregulation,fatty liver disease,liver fibrosis,and mitochondrial and endoplasmic reticulum lesions in mice.The infiltration of macrophages,mast cells,and natural killer cells varied between the model and treatment groups.mmu-miR-141-3p(a differentially expressed miRNA),Zcchc24(a differentially expressed mRNA),and Zcchc24(a differentially expressed protein)constituted the miRNA-mRNA-protein regulatory axis involved in mediating the therapeutic effects of GTPs on DEHP-induced liver damage in mice.CONCLUSION This study demonstrated that GTPs mitigate DEHP-induced liver dysfunction,blood lipid dysregulation,fatty liver disease,and partial liver fibrosis,and regulate immune cell infiltration.Additionally,an important miRNAmRNA-protein molecular regulatory axis involved in mediating the therapeutic effects of GTPs on DEHP-induced liver damage was elucidated.

Glycerin Monostearate Aggravates Male Reproductive Toxicity Caused by Di(2-ethylhexyl)Phthalate in Rats

Human beings are increasingly exposed to phthalates,which are a group of chemicals used to make plastics more flexible and harder to break,and simultaneously ingesting abundant food emulsifiers via daily diet.The purpose of this study was to investigate the effect of the food emulsifier glycerin monostearate(GMS)on male reproductive toxicity caused by di(2-ethylhexyl)phthalate(DEHP,one of the phthalates)and explore the underlying mechanism.Thirty male Sprague-Dawley rats were randomly divided into control group,DEHP group and DEHP+GMS group.Rats in the DEHP group and DEHP+GMS group were orally administered with 200 mg/kg/d DEHP with or without 20 mg/kg/d GMS.After 30 days of continuous intervention,it was found that the serum testosterone level was significantly lowered in DEHP group and DEHP+GMS group than that in control group(P<0.01).The serum testosterone level and the relative testis weight were significantly decreased in the DEHP+GMS group as compared with those in the DEHP group and control group(P<0.05).More spermatids were observed to be shed off in DEHP+GMS group than in DEHP group.The expression levels of cell cycle checkpoint kinase 1(Chkl),cell division cycle gene 2(Cdc2),and cyclin-dependent kinase 2(CDK2)were down-regulated in DEHP group,and this tendency was more significant in DEHP+GMS group(P<0.05 or P<0.01).There was no significant difference in the P-glycoprotein(P-gp)expression between DEHP group and control group.However,P-gp was markedly down-regulated in DEHP+GMS group(P<O.Ol).The results indicated that the food emulsifier GMS aggravated the toxicity of DEHP on male reproduction by inhibiting the cell cycle of testicular cells and the expression of P-gp in testis tissues.

Urine Metabonomic Analysis of Interventions Effect of Soy Isoflavones on Rats Exposed to Di-(2-ethylhexyl) Phthalate

Objective Di-(2-ethylhexyl) phthalate(DEHP) is a ubiquitous environmental contaminant.As an endocrine disruptor,it seriously threatens human health and ecological environmental safety.This study examines the impact of intervention with soybean isoflavones(SIF) on DEHP-induced toxicity using a metabonomics approach.Methods Rats were randomly divided into control(H),SIF-treated(A,86 mg/kg body weight),DEHP-treated(B,68 mg/kg),and SIF plus DEHP-treated(D) groups.Rats were given SIF and DEHP daily through diet and gavage,respectively.After 30 d of treatment,rat urine was tested using UPLC/MS with multivariate analysis.Metabolic changes were also evaluated using biochemical assays.Results Metabolomics analyses revealed that p-cresol glucuronide,methyl hippuric acid,N1-methyl-2-pyridone-5-carboxamide,lysophosphatidycholine [18:2(9 Z,12 Z)] {lyso PC [18:2(9 Z,12 Z)]},lyso PC(16:0),xanthosine,undecanedioic acid,and N6-acetyl-l-lysine were present at significantly different levels in control and treatment groups.Conclusion SIF supplementation partially protects rats from DEHP-induced metabolic abnormalities by regulating fatty acid metabolism,antioxidant defense system,amino acid metabolism,and is also involved in the protection of mitochondria.

Impairment of Di(2-Ethylhexyl) Phthalate on Cellular Immunity in Kunming Mice

Immunity is crucial to the health of animals and it can determine their survival and fitness. Di(2-ethylhexyl) phthalate (DEHP) is widely used as a plasticizer and hence is the most abundant phthalate in the environment. Exposure to DEHP is of great concern for human health. In the present study, we tested the hypothesis that exposure to DEHP would suppress T cell-mediated immunity in mice. Twenty adult male Kunming mice were randomly assigned into the control (n = 10) and the DEHP treatment (n = 10) groups. Both groups have free access to food and water, while the mice in the latter group drank DEHP solution (2000 mg/L) for 42 days. T cell-mediated immunity assessed by phytohaemagglutinin (PHA) response was depressed in the DEHP treated mice compared with the controls, however, wet thymus and spleen mass, white blood cells were not influenced by DEHP treatment. Taken together, different immunological parameters responded differently to DEHP treatment in Kunming mice.

Synergistic extraction of rare earth by mixtures of 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester and di-(2-ethylhexyl) phosphoric acid from sulfuric acid medium

The extraction of Nd^3＋ and Sm^3＋, including the extraction and stripping capability as well as the separation effect of Nd^3＋ or Sm^3＋, from a sulfuric acid medium, by mixtures of di-（2-ethylhexyl） phosphoric acid （HDEHP, H2A2（0）） and 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester （HEH/EHP, H2L2（0）） were studied. The distribution ratios and synergistic coefficients of Nd^3＋ and Sm^3＋ in different acidities were also determined. A synergistic extractive effect was found when HDEHP and HEH/EHP were used as mixed extractants for Sm^3＋ or Nd^3＋. The chemical compositions of the extracted complex were determined as Nd.（HA2）2-HL2 and Sm.（HA2）2-HL2. The extraction equilibrium constants, enthalpy change, and entropy change of the extraction reaction were also determined.

An Estimation of the Daily Intake of Di(2-ethlhexyl) Phthalate(DEHP) among Workers in Flavoring Factories

Objective To estimate the daily intake of DEHP among workers in flavoring factories. Methods 71 workers in two flavoring manufacturers, 27 administrators in those factories and 31 laboratory technicians in a research institute were recruited and assigned to exposure group, control group 1 and control group 2 respectively. Their urinary DEHP metabolites, mono（2-ethylhexyl） phthalate （MEHP）, mono-（2-ethyl-5-hydroxyhexyl） phthalate （MEHHP）, mono-（2-ethyl-5-oxohexyl） phthalate （MEOHP）, were detected by isotope dilution-ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）. The urinary metabolites concentrations were converted into DEHP intake levels using two pharmacokinetic models： the urine creatinine-excretion （UCE） one and the urine volume （UV） one. Results No significant differences were found among the three groups. Based on the urinary concentrations of Z3MEHP, we got a median daily DEHP intake of 3.22 or 1.85 μg/kg body-weight/day applying the UV or UCE models respectively. Depending on the UV model, three subjects （2.34%） exceeded the RfD value given by US EPA and the P50 of estimate daily DEHP intakes accounted for 16.10% of the RfD value. No subjects exceeded the limitation depending on the UCE model. Conclusion The workers in flavoring factories were not supposed to be the high DEHP exposure ones and their exposure level remained at a low risk.

Solvent extraction equilibrium of dysprosium(Ⅲ) from nitric acid solutions with 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester

In view of the importance of solvent extraction of rare earth metals with the acidic organophosphorous reagent,the development of a chemically based model applicable to high concentration is desired.In the present study,the equilibrium distribution of dysprosium(Ⅲ)between an aqueous nitric acid solution and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A)was measured in the range of an initial aqueous dysprosium(Ⅲ)concentration from 1.0×10-3to 1.0×10-1kmol/m 3and PC88A concentration from 0.16 to 0.65 kmol/m3in Shellsol D70 as the diluent.The obtained data were analyzed using the chemically based model in order to correlate the equilibrium distribution ratios.In this model,dysprosium(Ⅲ)was assumed to be extracted with the PC88A dimer as a 1:3 complex,the activities were considered for the aqueous species,and the effective concentration of the PC88A dimer was calculated using Alstad's empirical equation.As a result,the apparent extraction equilibrium constant was determined to be 253(kmol·m- 3)-2with an excellent correlation between the experiment and calculation results in the wide range of the logarithm of the distribution ratio from-2 to 3.5.In conclusion,the methodology in this model would be effective for quantitative description of solvent extraction behavior of general rare earth elements as well as dysprosium.

Synergistic extraction of praseodymium with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester and 8-Hydroxyquinoline

The synergistic extraction of Pr^3＋ from hydrochloric medium using mixture of 2-ethylhexyl phosphonic acid mono- 2-ethylhexyl ester （P507, HL） and 8-Hydroxyquinoline （HQ） in heptane was investigated. The effect of equilibrium of aqueous acidity on extraction of Pr^3＋ was discussed. The effect of extractant concentraction, different diluents, equilibrium time and acetate ion concentration oil extraction reaction were also studied. With a method of double-logarithmic slope, composition of the extracted species on 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester and 8-Hydroxyquinoline was derived. The result shows that the synergistic extraction system not only overcomes emulsification of 8-Hydroxyquinoline, but also shows perfect capacity of synergistic extraction. The largest synergistic enhancement factor can be calculated to be 5.49 at pH 3.6 for Pr^3＋.

Reducing children’s exposure to di(2-ethylhexyl)phthalate in homes and kindergartens in China:Impact on lifetime cancer risks and burden of disease

Exposure to di(2-ethylhexyl)phthalate(DEHP)in the indoor environment has been linked with significant health risks for Chinese children.Multi-phase DEHP concentrations in Chinese residences and kindergartens were estimated using a mass balance model based on the current baseline condition and control strategies(i.e.,increasing ventilation rate,reducing area of sources,using mechanical ventilation systems,and using portable air cleaners).The health benefits of each control strategy were quantified as the reduction in lifetime cancer risks(LCR)and burden of disease(BoD).In the current situation,the mean LCR and disability-adjusted life years(DALY)number attributable to indoor DEHP exposure for Chinese children were around 6.0×10^(−6) and 155 thousand,respectively.The mean LCR and DALY might be reduced by 25%-54%and 16%-40%,respectively,by increasing air exchange rates by 100%,reducing the use of source materials by two-thirds or deploying commercial air cleaners in naturally ventilated buildings.Meanwhile,avoidable DALYs could result in a reduction of mean economic losses of 2.2-5.3 billion RMB.Mechanical ventilation systems with filtration units may not be helpful for reducing children’s health risks.House-specific and tailor-made control measures are critical in lowering indoor exposure to DEHP to promote sustainable buildings and children’s health in China.

Maslinic acid supplementation prevents di(2-ethylhexyl)phthalate-induced apoptosis via PRDX6 in peritubular myoid cells of Chinese forest musk deer

Chinese forest musk deer(FMD),an endangered species,have exhibited low reproductive rates even in captivity due to stress conditions.Investigation revealed the presence of di(2-ethylhexyl)phthalate(DEHP),an environmental endocrine disruptor,in the serum and skin of captive FMDs.Feeding FMDs with maslinic acid(MA)has been observed to alleviate the stress response and improve reproductive rates,although the precise molecular mechanisms remain unclear.Therefore,this study aims to investigate the molecular mechanisms underlying the alleviation of DEHP-induced oxidative stress and cell apoptosis in primary peritubular myoid cells(PMCs)through MA intake.Primary PMCs were isolated and exposed to DEHP in vitro.The results demonstrated that DEHP significantly suppressed antioxidant levels and promoted cell apoptosis in primary PMCs.Moreover,interfering with the expression of PRDX6 was found to induce excessive reactive oxygen species(ROS)production and cell apoptosis in primary PMCs.Supplementation with MA significantly upregulated the expression of PRDX6,thereby attenuating DEHP-induced oxidative stress and cell apoptosis in primary PMCs.These findings provide a theoretical foundation for mitigating stress levels and enhancing reproductive capacity of in captive FMDs.

Association of Di(2-ethylhexyl)Phthalate Exposure with Reproductive Hormones in the General Population and the Susceptible Population:A Systematic Review and Meta-Analysis

Di(2-ethylhexyl)phthalate(DEHP),an environ-mental endocrine disruptor,has hormone-like activity and endocrine-disrupting effects.However,the types of reproductive hormones associated with DEHP vary across the studies.Thus,we conducted a systematic review and meta-analysis to pool existing epidemiological evidence.We searched three databases up to January 31,2024,for eligible original studies to ultimately include 37 studies from eight countries with a total of 28911 participants.DEHP exposure was evaluated with urinary metabolites.Since the main types,production sites,blood concentrations,and functions of reproductive hormones differ between men and women,we reported the combined effect values by gender.Subgroup analyses were conducted by age,subfertility status,and the national sociodemographic index(SDI)level.Furthermore,the effect of maternal exposure during pregnancy on children’s reproductive hormone levels was analyzed separately.Overall,in general,in men,DEHP was positively correlated with sex hormone binding-globulin(SHBG)and adversely correlated with total testosterone(TT),free androgen index(FAI),and follicle-stimulating hormone(FSH).Results indicated that among men of reproductive age,DEHP exposure was associated with more significant hormonal suppression in infertile men compared with fertile men.Notably,age subgroup analysis among women revealed that postmenopausal women were more vulnerable to DEHP,which was related to lower TT and estradiol(E2).However,this study did not observe a significant association between prenatal DEHP metabolites and reproductive hormone levels in children.Our research identifies the most susceptible hormones(androgen suppression)after DEHP exposure and suggests that infertile men and postmenopausal women are in great need of more attention as sensitive populations.

Aquatic toxicity of di (2-eihylhexyl) phthalate to duckweeds

This study is concerned with the effects of di （2-ethylhexyl） phthalate （DEHP） on two kinds of duckweeds （Spirodela polyrhiza and Lemna minor）.The results indicate that DEHP has aquatic toxicity to Spirodela polyrhiza at 0.4 mg/L and to Lemna minor at over 0.1 mg/L by changing their physiologic-biochemical characteristics.The contents of duckweed chlorophyll and soluble protein decrease with increasing DEHP concentration after 7 d of exposure.DEHP shows the stimulating role in catalase （CAT） and superoxide dismutase （SOD） systems at relative low levels.At 0.01 mg/L and 0.005 mg/L,SOD activities of Spirodela polyrhiza and Lemna minor reach their peak values respectively,while CAT activity reaches its maximum value at 0.05 mg/L and 0.01 mg/L.When DEHP levels are too high,the protection enzyme system would be destroyed and plant growth is inhibited.The analysis of malondialdehyde （MDA） and Fourier transform infrared spectroscopy manifest that DEHP could affect the tested duckweeds by destroying its cell membranes,and Spirodela polyrhiza is more resistant to DEHP exposure than Lemna minor.

蛋壳型Ru/Al_(2)O_(3)催化剂的制备及其对邻苯二甲酸酯的加氢活性

采用等体积浸渍法,通过改变Ru前体溶液pH制备了一系列蛋壳型Ru/Al_(2)O_(3)催化剂,利用SEM、电子探针微区分析、XRD、H_(2)-TPR等方法考察了不同前体溶液对催化剂Ru活性组分分布的影响,并以邻苯二甲酸二(2-乙基己)酯(DEPH)为反应物,评价了催化剂的加氢性能。实验结果表明,随前体溶液pH升高,活性组分Ru浸渍厚度变薄,形成蛋壳型催化剂。活性组分Ru浸渍厚度较小时,反应受内扩散影响较小;Ru浸渍厚度较大时,反应受内扩散影响较大。Ru浸渍厚度为190μm时,所制备催化剂对DEPH的加氢活性最高。

Primary neuronal-astrocytic co-culture platform for neurotoxicity assessment of di-(2-ethylhexyl) phthalate

Plastics such as polyvinyl chlorides （PVC） are widely used in many indoor constructed environments; however, their unbound chemicals, such as di-（2-ethylhexyl） phthalates （DEHP）, can leach into the surrounding environment. This study focused on DEHP＇s effect on the central nervous system by determining the precise DEHP content in mice brain tissue after exposure to the chemical, to evaluate the specific exposure range. Primary neuronal-astrocyte co-culture systems were used as in vitro models for chemical hazard identification of DEHP. Oxidative stress was hypothesized as a probable mechanism involved, and therefore the total reactive oxygen species （ROS） concentration was determined as a biomarker of oxidative stress. In addition, NeuriteTracer, a neurite tracing plugin with ImageJ, was used to develop an assay for neurotoxicity to provide quantitative measurements of neurological parameters, such as neuronal number, neuron count and neurite length, all of which could indicate neurotoxic effects. The results showed that with 1 nmol/L DEHP exposure, there was a significant increase in ROS concentrations, indicating that the neuronal-astrocyte cultures were injured due to exposure to DEHP. In response, astrocyte proliferation （gliosis） was initiated, serving as a mechanism to maintain a homeostatic environment for neurons and protect neurons from toxic chemicals. There is a need to assess the cumulative effects of DEHP in animals to evaluate the possible uotake and effects on the human neuronal system from exoosure to DEHP in the indoor environment.

Cytotoxic effects of mono-（2-ethylhexyl） phthalate on human embryonic stem cells

Background Mono-（2-ethylhexyl） phthalate （MEHP）, the metabolite of di-（2-ethylhexyl） phthalate （DEHP）, was suspected to be toxic to human embryos. This study contributes to investigating its toxic effects by an embryonic stem cell test （EST） based on two human embryonic stem cell （hESCs） lines. Methods CH1 established in our own lab and H1, a federally registered cell line were two human embryonic stem cell lines used in this test. Four endpoint measurements were performed consisting of cell viability, proliferation ability, apoptosis as well as changes of gene expression patterns after spontaneous differentiation were determined. For measuring effects on the first three endpoints, the cells were treated with various concentrations of MEHP dissolved in dimethyl sulfoxide （DMSO） and only with DMSO which served as control and harvested after 5 days. For measuring effects during spontaneous differentiation, the RNA of embryoid bodies （EBs） formed after 8 days＇ MEHP exposure was collected and changes in differentiation specific gene expression patterns were analyzed by quantitative real time RT-PCR. Results As a result the viability and proliferation ability of both cell lines decreased significantly at 1000 μmol/L MEHP, while there was no effect on apoptosis or cell morphology. In addition MEHP also changed the gene expression pattern in the EBs of both cell lines. Conclusion MEHP in a high dose was cytotoxic and affected the development of hESCs, which indicates its embryo toxicitv in human embrvos.

PAEs对原代培养的大鼠脂肪细胞PPAR-γ2表达的影响

目的:观察邻苯二甲酸酯类化合物(Phthalate acid esters,PAEs)对原代培养的大鼠脂肪细胞过氧化物酶体增殖剂激活受体-γ2(Peroxisome prolifcrator activated receptor gamma 2,PPAR-γ2)mRNA表达的影响。方法:对脂肪细胞进行PAEs染毒培养,观察脂肪细胞多方面的变化,评价PAEs对脂肪细胞的影响。主要实验:①显微镜每天观察脂肪细胞的形态变化;②油红O染色提取法和MTT比色法检查脂肪细胞的生长状况;③提取脂肪细胞的总RNA,通过逆转录PCR实验,分析PPAR-γ2 mR-NA的表达情况。结果:①PAEs处理过的脂肪细胞由最初的小圆形变化为梭形最后变成椭圆形,大鼠脂肪细胞内出现脂肪颗粒,并逐渐增加,最后部分脂肪颗粒融合为较大的脂肪颗粒,符合脂肪细胞的发育规律。②随着培养液中PAEs浓度的增加,大鼠脂肪细胞产生的脂肪颗粒数量增多。③PPAR-γ2的表达随着PAEs浓度的增加而增加。结论:可以认为PAEs通过增强PPAR-γ2表达来促进脂肪细胞的生长发育,研究结果将会为研究PAEs与肥胖的关系提供科学依据,为进一步研究PAEs对健康的影响提供了一个新的思路。

环境水体中邻苯二甲酸二(丁、2-乙基己基)酯的高效液相色谱分析方法研究

建立了环境水体中邻苯二甲酸二丁酯、邻苯二甲酸二(2-乙基己基)酯的固相萃取-高效液相色谱监测分析方法。样品经Wondasep C18固相萃取小柱富集,再以流动相进行梯度洗脱的色谱条件下,使邻苯二甲酸二丁酯、邻苯二甲酸二(2-乙基己基)酯完全分离。方法线性关系良好(r>0.9997),经萃取后,方法测定下限分别为邻苯二甲酸二丁酯0.00008 mg/L,邻苯二甲酸二(2-乙基己基)酯0.00003 mg/L。采用该方法分析了3个环境水体实际水样,邻苯二甲酸二丁酯和邻苯二甲酸二(2-乙基己基)酯的回收率分别在83.6%~94.7%之间和76.3%~81.2%之间,相对标准偏差在0.21%~2.97%之间。结果表明:该方法操作简单、回收率稳定、灵敏度高,适用于环境水体中邻苯二甲酸二(丁、2-乙基己基)酯的批量监测。

Plastic Additives Decrease Agrin-Induced Acetylcholine Receptor Clusters and Myotube Formation in C2C12 Skeletal Muscle Cell Culture

Common additives in plastics such as bisphenol A (BPA) or phthalates like di-(2-ethylhexyl) phthalate (DEHP) are environmental estrogens that have been shown to be endocrine disruptors in some experimental animal models. This project used the C2C12 cell culture model to examine how exposure to BPA or DEHP affects two aspects of skeletal muscle development, the fusion of myoblasts into myotubes and agrin-induced clustering of acetylcholine receptors (AChRs). During myotube formation AChRs cluster spontaneously. Treatment with motor neuron derived agrin increases the frequency of AChR clusters through an agrin signaling pathway that also clusters other postsynaptic components of the neuromuscular synapse. For this project C2C12 cells were exposed to BPA or DEHP while myoblasts fused into myotubes. After exposure to 10 μM BPA or 100 μM DEHP the frequency of agrin-induced AChR clusters decreased. In addition, myotube formation decreased as a higher percentage of nuclei remained in myoblasts. Furthermore, BPA or DEHP reduced the amount of the myogenic regulatory factor myogenin. This suggests that BPA and DEHP decrease AChR clustering by reducing myogenin. Moreover, plastic additives like BPA and DEHP may pose a risk for skeletal muscle development in humans.

SOLVENT EXTRACTION OF LANTHANIDES BY 2-ETHYLHEXYLPHOSPHONIC ACID MONO-2-ETHYLHEXYL ESTER

The chemistry of extraction of lanthanide and yttrium by 2-ethylhexylphosphonic acidmono-2-ethylhexyl ester in n-dodecane from nitric acid is described. By M W determination, NMR and the slope method, the extraction reaction is studied.Based upon elementery analyses, IR, NMR as well as MW determination, the compositions ofthe complexes formed with La（NO3）3 and Nd（NO3）3 are studied. Both the standard enthalprchanges（-△H°） and the relative free energy and entropy changes （-△Zr°）（△SPr°）of the ex-.traction reaction are also estimated. The regularity of the variations of Kea（concentrationequilibrium constant）, -△AZr° and △Sr°reveals the tetrad effect. The average separationfactor of the adjacent lanthanides is calculated to be as high as 3.04.